Technical Field
This invention relates to a wall which provides dampening of sound and, in particular, a quick and economical method of constructing a double-stud wall providing significantly improved sound dampening characteristics, while being low in cost.
Description of the Related Art
At present, many environments desire to have effective sound dampening between adjacent rooms. In many commercial construction locations, such as hospitals, office buildings, and the like, it is desired to have low sound transmission between adjacent rooms. Presently, one method by which this is accomplished is to place thick layers of acoustic insulation in the wall between the rooms and to place studs on either side of the wall. This has the disadvantage of being expensive and time-consuming to construct. Other techniques include placing multiple layers of drywall on the studs of the wall, or specialty drywall products which have high acoustic dampening properties. The disadvantage of this approach is that it is expensive because of the cost of extra materials and labor to install said materials or the high cost of sound dampening specialty Drywall and, in addition, is also time-consuming, which raises labor cost.
One measure of the sound dampening characteristics of a wall is called the sound transmission coefficient (STC). The STC of a particular wall provides an indication of the attenuation which the wall provides for acoustic waves and, thus, a good indication of the sound dampening that it provides between adjacent rooms. A standard sheet of drywall, which is a low gypsum board, may have an STC of approximately 26. Thicker drywall may have STCs in the range of 28 and 29. Two drywall panels placed abutting each other, if each is a standard gypsum board, will have an STC of 34. Generally, an STC in the range of 35 or lower indicates that a significant amount of sound will pass from one room to another and the wall provides little attenuation. In order to obtain attenuation in the range of 55-60, which is often desired, it is currently the practice to create two walls, each of which has a set of studs to support the drywall, and then place one or more layers of sound-attenuation material, such as an acoustic dampening insulation or other material, between them. While such a structure is sufficient to obtain an STC in the range of 55 or higher, it is expensive, time-consuming to construct, and also takes some skill to properly assemble.
Past attempts to increase the STC of wall assemblies have focused on specialty products which, in many instances, are prohibitively expensive. Other techniques have been to add significant layers of conventional materials that increase the mass, which, while it will increase the STC rating, adds significant cost as well as additional time, and takes up more space. Other attempts have been to use multiple phases in the wall assembly in order to add layers of conventional construction material at the same surface to achieve a higher STC rating. However, this increases the time in which construction can be completed and also increases the cost. The schedule is affected negatively if multiple phases are used for the construction due to more materials having to be installed at the site, which, in turn, requires a longer duration for the phase of work, which impacts the construction schedule along with the additional time. Another downside of using multiple layers of materials or multiple phases is the reduction in floor area that happens if additional layers of materials are added to the wall assembly.